Imaging Simulation Of Remote-sensing Satellite Based On Digital Earth

Nowadays, remote-sensing plays an increasingly important role in national production activities. With long range and wide field, remote-sensing satellite allows us to look at the earth in a new point of view from outerspace, and makes great convenience to national defense, scientific research and our daily lives. The simulation of remote-sensing satellite’s running track and imaging processes, as well as the imaging results at any time and different environments, is of great significance in the analysis of satellite’s performance on track and the evaluation of imaging quality.In this paper, We have used OpenSceneGraph(OSG) engine as tool to build a remote-sensing satellite imaging simulation system based on digital earth, which combined satellite orbital dynamics theory and satellite imaging simulation theory. The main work of this paper are outlined as follows:1. The remote-sensing satellite orbit model and calculation method have been studied. We analyzed the relationship between the conversion of remote sensing satellite orbit parameters, the track characteristics, and list some common remote sensing satellite orbit parameters. Based on the relationship between the orbital parameters and its orbit, and the two-body problem of satellite, We summarized the calculation method of satellite orbit at any time, and have a brief introduction to the overall index of remote sensing satellite orbit2. The time and coordinate systems which are related to satellite imaging have been studied. We compared the differences among Sidereal Time, Universal Time, and the Atomic Time system, analyzed the relationship between Julian Day and the calendar, and studied the meaning of Two-Line Orbital Element. We also summed up the transform from earth inertial coordinate system to the geographic coordinate system, the track coordinates, satellite body coordinate system and the local level coordinate system, as well as the convert between geographic rectangular coordinate and geographic latitude and longitude coordinate.3. The remote-sens ing satellite imaging sensor model and effect have been searched. We analyzed the sensor model based on collinear equation and sensor model based on affine transformation respectively. We studied the image motion effect caused by satellite flutter and movement. The atmospheric attenuation and turbulence effect, the effect of optical system and detector effect of imaging system have been analyzed and summarized.4. The modeling of digital earth scene based on OSG have been studied. According to OSG scene rendering theory, we analyzed the features of scene simulation module structure and organization of OSG, and summarized the installation, compilation and configuration methods. By using the OSG tool, we established a digital earth with three-dimensional sphere and the underlying texture, achieved partial high-definition images and elevations to the earth, then added the sun light and geographic information to the scene.5. The simulation of remote sensing satellite image has been achieved. First, we have used STK satellite tools to simulate the running track and coverage area of the Landsat-7 remote-sensing satellite, and developed a imaging simulation software based on our digital earth system, with the help of MFC development environment platform in C++ language. Then, we considered some cases with different imaging environments and simulated the running track and imaging results, analyzed the imaging effect, including the atmospheric effect and the effect of imaging system At last, we compared our simulation systems to STK software, the result have showed that using the digital earth system which based on OSG is reliable and has a good expansibility.